webCamTexture playing in high resolution lags

Hi all, I am using webCamTexture to grab the webcam data and show the images on a raw image with a Logitech C920 webcam.

I set the resolution as:

 webcamTexture = new WebCamTexture("HD Pro Webcam C920", 1920, 1080, 30);

However it lags and the fps is only around 10.

What should I do to avoid lagging when having high-resolution images?

I have tried the AVproCamera and choose the mjpg format instead of YUY2. The fps is around 30 which is acceptable.

I wonder if there is a way to use mjpg format while using webCamTexture.

Anyone can help?

Thanks in advance!